Torque-measuring device



y 21, 1963 G. WIGGERMANN 3,383,911

TORQUE-MEASURING DEVICE Filed April 1, 1966 2 Sheets-Sheet 2 United States Patent 0 3,383,911 T GRQUE-MEASURENG DEVICE Georg Wiggermann, Kressbronn am Bodensee, Germany, assigncr to Reiners & Wiggermann Maschinenfabrik, Kressbronn am Bodensee, Germany, a corporation of Germany Continuation-impart of application Ser. No. 448,997, Apr. 19, 1965. This application Apr. 1, 1966, Ser. No. 539,361 Claims priority, application Germany, Apr. 26, 1964, R 37,730; Apr. 5, 1965, R 40,326 10 Claims. (Cl. 73--136) ABSTRACT OF THE DISCLOSURE Torque measuring device for coupling a drive shaft to a driven member which includes a vane disc having fluid passage means formed therein and a splined bore extending axially therethrough, hub means extending through the splined bore and adapted to be driven by the drive shaft, the hub means being in the form of a sleeve having axially extending exterior splines for releasably coupling the hub means to the vane disc and for directing fluid to the passage means, means for driving the driven member, the driven member driving means and the vane disc defining compression chambers communicating with the passage means, and pressure-transmitting means communicating with the compression chambers through the axially extending splines for supplying fluid thereto, whereby fiuid pressure within the compression chambers and the pressure-transmitting means is indicative of the torque eing transmitted from the drive shaft to the driven member.

This application is a continuation-in-part of my copending application Ser. No. 448,997, filed on Apr. 19, 1965, and entitled Hydrostatic Torque-Measuring Device.

My invention relates to hydrostatic torque-measuring devices in which a power-transmitting coupling has inner and outer rotor members which define between themselves compression chambers, the device including structure for measuring the pressure in these chambers.

It is a primary object of my invention to provide further improvements in hydrostatic torque-measuring devices.

Ideally, a device of this type should have a small size, universal utility, and a low cost. These three properties of the hydrostatic torque-measuring device, or measuring coupling, depend to a large extent one upon the other, and it is an object of my invention to improve all three properties.

It has already been proposed to reduce the size of the device by mounting the inner rotor member, which takes the form of a vane disc, directly on a drive shaft by forming this vane disc with a hub which directly receives the drive shaft, so that in this way a mounting flange conventionally required to attach the device to a drive shaft can be eliminated and instead the measuring coupling itself is directly mounted on the drive shaft.

While this construction will indeed shorten the size of the device in the axial direction, it nevertheless carries with it the disadvantage of requiring the device to have a relatively large outer diameter. The reason for this. is that such a hub of the vane disc must be formed with a plurality of axially extending bores which require the hub of the vane disc to have an undesirably large wall thickness. This requirement also is of disadvantage in connection with the universal utility of the vane disc and its manufacturing cost. This feature prevents low-cost mass production of the measuring coupling and in par- 3,383,911 Patented May 21, 1968 ticular does not permit a supply of these couplings to be maintained in stock. The reason for this is that every individual purchaser of the measuring coupling will require the hub of the vane disc to be formed with a bore which must be adapted to the particular drive shaft with which the measuring coupling is to be used, and this bore can only be formed in the course of manufacture of the vane disc. As a result, such vane discs must be individually manufactured, for these practical reasons, and therefore undesirably high costs and undesirably long times are required to fill orders.

The highly desirable compact measuring coupling of relatively small outer diameter requires not only a vane disc which has a hub of as small wall thickness as possible, but also the largest possible number of vanes. A large number of vanes will also result in a compact device of small diameter. The result of this latter requirement, however, is an increase in the oil requirements for the compression chambers, and it is only by way of a hub of large wall thickness that it is possible to provide not only the large number of oil passages but also the keyway required to transmit the drive from the drive shaft through the hub to the vane disc.

It is therefore among the more specific objects of my invention to avoid these latter drawbacks.

In particular it is an object of my invention to provide for a vane disc of the above type a hub means which can transmit a drive from the drive shaft to the vane disc and which at the same time is separable from and interchangeably connected with the vane disc. As a result the measuring coupling itself can be formed as an independent unit in large numbers and can be kept in storage so that a supply of these devices is always available. Also, a supply of interchangeable hub means, the cost of which is such a small fraction of the total cost as to hardly be noticeable, can be stored so that a supply is always available. Then, in order to fill an order it is only necessary to very quickly adapt the bore of a particular hub means in its size and shape to that required by the particular purchaser, and this hub means which is now suited for the particular order is assembled with a completely finished measuring coupling which is readily available from the supply which is maintained on hand.

Of course, the construction of the hub means as an interchangeable individual part carries with it considerable difficulties. Thus, for example, where the measuring coupling has a vane disc provided with a large number of vanes it is difficult to provide the required fixed connection between the hub means and the vane disc and at the same time provide also the large number of oil passages while maintaining oil-tightness at the joint between the hub means and the vane disc.

It is therefore an object of my invention to solve these latter problems.

In order to be able to supply a relatively large number of compression chambers with oil by Way of a device which includes a hub means of small wall thickness, it is a further object of my invention to provide a passage means for the fiow of oil having a construction which enables the several compression chambers to be supplied with oil from a num ber of passages even greater than the number of compression chambers themselves, so that an efficient full supply of oil to the compression chamber is guaranteed, and furthermore it is an object of my invention to provide for the passage means a sealing structure which will enable the flow of oil to take the required path without any undesirable leakage or faulty fluid communication between oil-containing spaces which should not communicate with each other.

In particular it is an object of my invention to provide one controlling structure which functions exclusively to e3 control the flow of oil to the compression chambers and an entirely distinct control structure which functions exclusively to control the discharge of oil from the compression chambers, as well as a sealing structure which reliably maintains these two distinct controlling structures fluidtightly separate from each other.

An additional object of my invention is to provide a hydrostatic torque-measuring device in which the measurements are not influenced by the speed of rotation. In order to fulfill this requirement it is necessary for the supply of oil to the compression chambers to take place at the same radial distance from the axis of the device as the discharge of oil from the compression chambers, and in addition it is required that the pressure-transmitting means which enables the pressure to be measured should also receive oil through passages at the same radial distance from the axis of the device. It is therefore an object of my invention to provide a construction which enables these latter requirements to be fulfilled in a very practical way.

The objects of my invention also include the provision of a hydrostatic torque-measuring device which requires less circumferential movement of the inner vane disc and the outer rotor housing one with respect to the other, than has heretofore been required, as well as to provide a structure where the circumferential dimensions of the compression chambers can be made smaller than was heretofore required.

Thus, one of the primary features of my invention resides in providing, in a hydrostatic torque-measuring device, a vane disc which is adapted to surround a coaxial drive shaft, with a hub means situated between the drive shaft and the vane disc, surrounded by the latter and operatively connected thereto for transmitting rotation from the drive shaft to the vane disc. This hub means of my invention is separable from and interchangeably connected with the vane disc.

My invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 shows in a longitudinal sectional elevation one possible embodiment of a hydrostatic measuring coupling according to my invention;

FIG. 2 is a side view, partly in longitudinal section, of a hub means of my invention;

FIG. 3 is a transverse section of the structure of FIG. 1 taken along line 33 of FIG. 1 in the direction of the arrows;

FIG. 4 is a transverse section of the structure of FIG. 1 taken along line 4-4 of FIG. 1 in the direction of the arrows, FIGS. 3 and 4 both being fragmentary transverse sections;

FIG. 5 is a side elevation of a bearing sleeve, shown partly in longitudinal section; and

FIG. 6 is a transverse section of the bearing sleeve of FIG. 5 taken along line 66 of FIG. 5 in the direction of the arrows.

Referring now to FIGS. 1, 3 and 4, there is illustrated therein a vane disc 31 having radially extending vanes 31a. The vane disc 31 forms one of a pair of rotor members of the measuring coupling of the invention. The other of the rotor members is in the form of a rotor housing 32 having inwardly directed vanes 32a and these vanes 32.1 are situated with relatively small clearance between the vanes 31a so as to define therewith the compression chambers 5. Thus, the circumferential dimensions of the vanes 31a and 32a are such that the inner vane disc 31 and the outer rotor housing 32 can turn one relative to each other to a limited extent. The compression chambers 5 which are thus defined between the vanes 31a and 32a will have their volume changed during operation with the volume of the chambers 5 on opposite sides of a given vane changing in opposed manners so that while the chamber 5' on one side of a given vane tends to decrease in volume the chamber on the other side tends to increase.

A hub means of the invention is provided for transmitting to the vane disc 31 rotary movement of a drive shaft which is received within the hub means, and as has been pointed out above it is one of the primary features of the invention to provide a hub means which is removably connected with and interchangeable with respect to the vane disc 31. The hub means of my invention takes the form of an elongated splined sleeve 33 having longitudinally extending exterior splines 4 (FIG. 2). This splined sleeve 33 is moved into the central opening of the vane disc 31 from the right toward the left, as viewed in FIG. 1, and the teeth or splines 34 of the sleeve 33 mesh with teeth 34a formed at the inner periphery of the vane disc 31, so that, as is particularly apparent from FIG. 3, the vane disc 31 and the hub means 33 are interconnected for rotary movement as a unit.

The rotor housing 32 is supported for rotary movement on the hub means 33 by means of a pair of ball bearings 3 which are respectively provided with inner race rings 35 which directly engage the hub means 33 at the outer tips of the teeth 34 thereof. These inner races 35 of the ball bearings 3 are seated directly on and are slidable with respect to the outer tips of the teeth 34- of the hub means 33.

As is apparent from FIGS. 1 and 2, the splines or teeth 34 of the sleeve 33 terminate short of the left end thereof, as viewed in FIGS. 1 and 2. Situated beyond the teeth 3 is a smooth exterior cylindrical surface portion of the sleeve 33, and seated on this smooth exterior cylindrical surface portion of the sleeve 33 is a bearing sleeve 36 the details of which are apparent from FIGS. 5 and 6. This bearing sleeve 36 has an inner smooth cylindrical surface slidably and snugly engaging the exterior surface of the sleeve 33 to the left of the teeth 34 thereof. A ring 37 is provided at its inner periphery with threads which are threaded onto mating threads at the left end of the sleeve 33, as viewed in FIGS. 1 and 2, and this ring 37 serves to press all of the components directly mounted on the hub means 33 against each other and between the ring 37 and a collar 33a integral with the sleeve 33 and situated at the end thereof opposite from the ring 37. Thus, the collar 33a takes the form of an integral flange of the sleeve 33 directed outwardly therefrom and directly engaging the right race ring 35 of the right bearing 3 of FIG. 1. As a result of this feature the pair of race rings 35 are pressed tightly against the opposed faces of the vane disc 31 and of course the bearing sleeve 36 is tightly pressed between the ring 37 and the left race ring 35, so that the bearin sleeve 36 is in this way fixed to the sleeve 33 while all of the components engage each other at their interfaces with a sufiicient pressure to provide absolute oil-tightness and thus all of the components which surround and directly engage the hub means 33 form the equivalent of a tubular pipe surrounding the latter.

The vane disc 31 is formed with part of the passage means for directing oil through the measuring coupling along a predetermined path and in a precisely controlled manner, as described below. For this purpose the vane disc 31 is formed in each of its vanes 310 with a pair of radially extending bores 31b and 31c. Thus, as is apparent from FIG. 1, there is one set of radial bores 31b formed in the vanes 31a and axially displaced to the left, as viewed in FIG. 1 with respect to the right or second set of radial bores 31c which are formed in the vanes 31a of the vane disc 31. At its inner periphery the vane disc 31 is formed with a plurality of axially extending grooves 31d which respectively communicate with the radial bores 3Tb at their inner ends. These relatively short grooves Said are situated between the teeth 34a and extend from the left face of the vane disc 31., as viewed in FIG. 1, up to but not beyond the bores 31b. This left set of radial bores 31b communicates at the outer ends of its bores 31b with axially extending bores 31a which extend to the left, as viewed in FIG. 1, from the several bores 31!), respectively, to the left face of the vane disc 31. Instead of individual grooves respectively communicating with the second set of radial bores 310 at the inner periphery of the vane disc 31, there is provided an annular groove 31 which is formed at the inner periphery of the vane disc 31 and which communicates with all of the radial bores 31c, and when the parts are assembled it will be noted that this groove 31] is in axial alignment with the groove 33a which is formed'in and surrounds the hub means 33. At their outer ends the second set of bores 310 respectively communicate with axially extending bores 31g which are respectively formed in the vane disc 31 and extend axially from the outer ends of the bores 31c to the right face of the vane disc 31, as viewed in FIG. 1.

A pressure-transmitting means 38 surrounds the bearing sleeve 36. The details of the pressure-transmitting means 38 are described to a greater extent in the abovementioned copending application. It is through this pressure transmitting means that the oil under pressure is connected with a suitable measuring device such as a pressure gauge. The pressure transmitting means 38 includes an annular housing which is turnably carried by a pair of slide rings 39 which are seated on the bearing sleeve 36, slidably surrounding and slidably engaging the latter. In order to be capable of connection with a stationary oil supply conduit and the measuring device the housing of the pressure-transmitting means 38 is formed with one or more internally threaded outer bore portions 40, and these bore portions 40 extend radially through a wall of the housing 38 to an inner peripheral surface thereof where these bores 40 communicate directly with the annular gap 41 which is defined between the pair of slide rings 39. These rings respectively have at their outer peripheries outwardly directed annular flanges engaging the opposed end faces of the wall which is formed with the radial bore or bores communicating with the threaded portions 40.

In accordance with a further feature of my invention the gap 41 defined between the slide rings 39 is axially aligned with an annular groove 36a which is formed at the exterior of the bearing sleeve 36. This bearing sleeve 36 is formed at its inner periphery with axially extending teeth 36b, and the groove 36a intersects the teeth 36b communicating directly with the gaps therebetween. This feature is particularly apparent from FIGS. 5 and 6. Thus, the smallest diameter of the groove 36a is somewhat smaller than the largest diameter of the teeth 36b. As a result the several gaps between the teeth 36b thus respectively communicate with the annular groove 36a through apertures 36c (FIGS. 5 and 6) which are of rectangular configuration and which result from the intersection of the annular groove 36a with the teeth 36b. The guiding of the pressure transmitting means 38 at the end faces of its wall which is formed with the bore communicating with the threaded connection 40 is brought about by way of the above-mentioned outwardly directed flanges at the outer peripheral edges of the slide rings 39, the outwardly directed flange of the left ring 39 of FIG. 1 engaging the threaded ring 37 while the outwardly directed flange of the right ring 39 of FIG. 1 engages an outwardly directed flange 36d formed integrally with the sleeve 36:

The hub means 33 is formed just to the left of its groove 33c, as viewed in FIG. 2, with an annular groove 33b which extends through the several teeth 34 of the sleeve 33. The vane disc 31 is provided at its inner periphery, just to the right of and extending beyond the right ends of the inwardly directed teeth 34a thereof with an exterior cylindrical surface 31h. This surface 31h extends from the right ends of the teeth 34a, as viewed in FIG. 1, up to the left end of the groove 31f which is formed in the vane disc 31. The groove 33b receives in its interior, under a certain pretension, a sealing ring 42 in the form of an O-ring made of an oil-resistant rubber, and in this way a sealing means is provided at the connection between the vane disc 31 and the hub means 33. The sealing ring 42 is supported at its right side, as viewed in FIGS. 1 and 2, by a ring 43 made of plastic or metal. In order to be able to introduce the ring 43 into the groove 33b this ring 43 may be made of two or more sections. Thus, with this construction of my invention it is possible to introduce the hub means 33 from the right toward the left, as viewed in FIG. 1, into the central aperture of the vane disc 31 with the teeth 34a of the latter entering into the gaps between the teeth 34 of the sleeve 33, and these teeth 34a can slide along the teeth 34 until the right ends of the teeth 34a, as viewed in FIG. 1 are flush with the left end of the grorove 33b, as viewed in FIG. 2. Thus, the mechanical connection between the hub means 33 and the vane disc 31 is situated to the left of the sealing ring 42. It is to be noted that the sealing means which is formed by the ring 42 is situated in a plane normal to the axis of the vane disc 31 and situated between the sets of radial bores 31b and 310 thereof. Therefore it is not possible for the sets of bores 31b and 31c to have fluid communication with each other at the inner periphery of the vane disc 31. As is described below, the pressure of the oil acts on the sealing ring 42 from the left, as viewed in FIG. 1, this pressure corresponding to the prevailing measuring pressure, and this force seeks to displace the sealing ring 42 into the gaps between the teeth 34 at the portions thereof situated between the grooves 33b and 33e. However, in order to prevent such pressing of the ring into the gaps between the teeth 34, the reinforcing or supporting ring 43 is provided extending across the gaps between the portions of teeth 34 situated between the grooves 33b and 33e, so as to reliably maintain the sealing ring 42 in its proper position within the groove 33b.

The rotor housing 32 has directed toward the pressure transmitting means 38 a side wall 32b, and between each pair of inwardly directed vanes 32a of the rotor 32 this side wall 32b is formed at its inner surface with a pair of recesses 32d in the form of a pair of circular bores extending axially from the inner surface of the wall 32b toward but terminating short of the outer surface thereof. These recesses 32d are situated along a circle whose radius is the same as that along which the bores 31s are situated.

Furthermore, the other side wall 320 of the rotor housing 32, this outer side wall 320 being situated more distant from the pressure transmitting means 38 than the side wall 32b, is formed at its inner surface, in the spaces between the several inwardly directed vanes 32:: with a pair of axially extending bores 32e which are situated along a circle of the same radius as that along which the several axial bores 31g are located. These circular bores 32e also extend from the inner surface of the Wall 32c toward but terminate short of the outer surface thereof. As is apparent from a comparison of FIGS. 3 and 4, the pair of recesses 32e formed at the inner surface of the wall 32c between each pair of vanes 32a are located directly next to each other, whereas the pair of recesses 32d at the opposite wall 32b between each pair of vanes 32a are relatively distant from each other.

In order to provide hydraulic communication between the pair of opposed faces of the vane disc 31, this disc 'is formed with a plurality of axially extending bores 311' the axes of which form elements of a cylinder whose axis coincides with the axis of the vane disc 31. As may be seen from FIG. 1, the several axial bores 31: are situated at the same radial distance from the axis of the vane disc 31 as the ball members of the pair of ball bearings 3.

As has been indicated above, the pressure transmitting means 38 is described in greater detail in my copending application referred to above. The structure of this pressure transmitting means is such that the measuring coupling will operate either in a vertical or in a horizontal attitude. The pressure transmitting means is provided with a discharge opening 38a through which the oil can communicate with a stationary recirculating conduit. As is indicated in FIG. 1, the wall 32b of the rotor housing 32 has a forwardly extending cylindrical portion 38b which terminates in an outwardly directed flange 38c having at its outer periphery a frustoconically shaped portion 38:] which extends over an inwardly directed frustoconical portion of the outer housing of the pressure transmitting means 38. The ring 37 terminates at its outer periphery in a similar flange which overlaps an inwardly directed flange .at the left end wall of the pressure tran-simtting means 38. In this way a labyrinth is formed with a resulting seal in the manner indicated in greater detail in my copending application referred to above.

At its end which is directed away from the pressure transmitting means 38, the rotor housing 32 is integrally formed with an outwardly directed flange 2a which serves to connect the rotor housing to a driven member to which the torque is transmitted through the measuring coupling of the invention. A cover 22 is screwed onto the flange 20 so as to close the measuring coupling of my invention and this cover 22 serves to center the flange of the driven component which is connected with the flange 2a. Also, the cover 22 provides a fluid-tight closure for the coupling. In the illustrated exampe the hub means 33 is formed with a cylindrical bore 33c which receives the shaft which drives the measuring coupling, and at its inner periphery the hub means or splined sleeve 33 is formed with a keyway 33d into which extends a key which is carried by the shaft which is received in the bore 33c. Thus, the measuring coupling of my invention is mounted directly upon the driving stub shaft or the like which is received in the bore 330, this stub shaft forming a power take-off for an electric motor or the like. The bore 33c of the hub means 33 is closed at its right end, as viewed in FIG. 1, by a wall extending transversely across the sleeve and carrying an axially positioned screw 33f which is adapted to be threaded into a threaded bore formed at the end of the shaft Which is received in the bore 33c so as to axially fix the unillustrated stub shaft in the measuring coupling of my invention.

The measuring coupling described above and shown in the drawings operates as follows:

The oil delivered to the connection 40 of the pressure transmitting means 38, which in principle remains stationary, fiows to the annular gap 41 between the rings 39 and into the annular groove 36a of the bearing sleeve 36 so as to reach the gaps between its inner teeth 36b. These teeth 36b are of the same size and angular distribution as the teeth 34 of the splined sleeve 33, so that the gaps between the teeth 36b form extensions of the gaps between the teeth 34, the teeth 36!) of course forming extensions of the teeth 34. In this way the oil will flow along the gaps between the teeth 34 of the hub means 33 partly into an annular recess 35a formed at the inner right periphery of the left bearin race 35 so as to flow from the recess 35a into the grooves 31d and partly directly into the grooves 31d from the gaps between the teeth 34. It will be noted that the inwardly directed teeth 34a of the vane disc 31 and the sealing ring 42 prevent the oil from flowing to the right along the hub means 33 beyond the set of radial bores 31b, so that in this way the oil flows into the left set of radial bores 31b and from the latter into the axial bores 31c respectively formed in the several vanes 31a of the vane disc 31.

When the vane disc 31. is angularly positioned with re spect to the rotor housing 32 so that the vanes 31a are situated midway between the vanes 32a, respectively, as indicated in FIG. 3, the control bores 31c overlap the recesses 32:! formed in the side wall 32b of the rotor housing 32, so that the oil can flow through these recesses 32d into the compression chambers situated on opposite sides of the vanes 31a. When the vane disc 31 and rotor housing 32 have the intermediate position with respect to each other illustrated in FIGS. 3 and 4, the recesses 32c formed in the wall 320 of the rotor housing are in communication with the compression chambers 5 so that the oil flows from the compression chambers into the recesses 32c which at this time communicate with the other set of control bores 31g, so that the oil after flowing through the compression chambers can reach the second set of radial bores 310. From the second set of radial bores 310 the oil flows into the annular groove 31 of the vane disc and into the annular groove 33a of the hub means on the opposite side of the sealing means 42, so that now the oil can continue to flow to the right, as viewed in FIG. 1, along the gaps between the teeth 34 at the portions thereof situated to the right of the groove 33c, as viewed in FIG. 2. The oil flows in this way around the right inner race ring 35 of FIG. 1 to the ball bearing 3 shown at the right of the vane disc 31 in FIG. 1. The oil will fill the chamber 44 defined between the closed end of the hub means 33 and the cover 22, and from this chamber 44 the oil will flow through the right bearing 3 of FIG. 1 into the several axial bores 31:. After flowing through the bores 31i the oil reaches the left ball bearing 3, as viewed in FIG. 1, so as to reach in this way the interior of the pressure transmitting means 38. From the interior of the pressure transmitting means 33 the oil can discharge through the outlet 38a.

Inasmuch as the above-described path formed by the passage means of my invent-ion provides no appreciable resistance to the flow of the usually small amount of oil, this passage means will provide no undesirable influence on the measured pressure. As soon as, however, a torque is transmitted from the hub means 33 through the coupling of my invention to the flange 2a, or in the reverse direction, a relative angular displacement will occur between the vane disc 31 and the rotor housing 32, and as a result of this angular displacement the oil supplied through the set of radial bores 31b seeks to flow into that one of the pair of chambers 5 on each side of each vane 31a which is of smaller volume, while the hydraulic connection between the radial bores 31b and the chambers 5 of increasing volume is continuously throttled to an increasing extent. The same relative angular movement between the vane disc 31 and the rotor housing 32 produces simultaneously at the opposed wall 32c of the latter in the recess 32c thereof a continuously increasing throttling of the flow from the chambers 5 of reducing volume to the discharge bores 310 While the cross section of the hydraulic path of flow from the chambers 5 of continuously increasing volume to the discharge bores 31c through the control bores 31g continuously increases. As a result there is produced between the fluid pressure of the oil in the compression chambers 5 of reducing volume and the pressure of the oil in the compression chambers 5 of increasing volume a pressure differential which is proportional to the torque and which corresponds to the desired measured pressure. The control of the flow of oil to and from the measuring coupling resulting from the relative rotation between the rotor members results in a condition where the circumferential force acting on the vanes as a result of the measuring pressure balances the circumferential force called for by the torque which is transmitted. The direction of relative rotation between the vane disc 31 and the rotor housing 32 is determined by the direction of rotation of the transmitted torque. As a result of the particular arrangement of the recesses 32d and 32:2, however, the particular direction of relative rotation between the rotor members has no influence on the measuring pressure which is developed or on the magnitude of the measurement.

The measuring pressure which is proportional to the prevailing torque is present in the oil supply passages through which the oil flows to the measuring coupling of my invention, so that this pressure is present at the connection 40 of the pressure-transmitting means 38. The stationary measuring device which is connected at 40 to the pressure transmitting means 38 can be calibrated to give direct torque readings. Furthermore it is possible to 9 actuate from the measured pressure regulating, control, or adjusting devices.

Of course, the principle of my invention can be practiced with structural details differing from the particular details described above. For example, instead of a hub means 33 having outer teeth it is possible to provide the hub rneans at least partly with inner teeth similar to the teeth at the inner periphery of the bearing sleeve 36. It is, however, one of the more important and more general features of my invention to provide for the flow of the oil to and from the vane disc 31 a flow path which extends along the exterior of the splined sleeve 33 which is removably connected with the vane disc 31.

It will be seen that with my invention the splines or teeth of the hub means 33 serve not only to transmit mechanical motion but also as conduits for the flow of oil to and from the vane disc. Of course, in order to enable the gaps between the teeth 34 to function as oil conduits it is necessary to cover these gaps, and this is brought about with my invention by directly mounting on the teeth 34 themselves the vane disc 31 as well as the inner race rings 35 of the ball bearings 33, these elements being pressed against each other by way of the threaded ring 37 and the flange 33a, as described above, so that they form in effect a tubular guide which cooperates with the gaps between the teeth 34 to form the oil passages therewith.

The depth of the teeth 34, considered in a radial direction, is extremely small, so that by eliminating the requirement of longitudinal bores for the oil flowing along the hub it is possible to provide a hub means 33 which has an extremely small wall thickness, thus resulting in the smallest possible exterior diameter for the hub. At the same time the gear teeth 34 provide the desired releasable connection between the hub and the vane disc, and the relatively large number of gaps between the gear teeth results in a total gross sectional area for the flow of oil which is sufficiently great to provide for the required supply of oil to a relatively large number of compression chambers which, in fact, can have as large a number as practical considerations will permit. In view of the fact that the measuring coupling of my invention has the smallest possible exterior diameter, such a relatively large number of compression chambers is required, and by utilizing gear teeth or splines to define oil passages between themselves, it is nevertheless possible to provide for the required oil flow. As was mentioned above, the hub means of my invention can be manufactured in advance of any particular orders and can be maintained in storage so that a supply of these hubs is readily available. All that is required is to adapt the inner bore 330 to the requirements of a particular purchaser when a particular order comes in, and this finishing of the inner bore 330 can be carried out very quickly in an extremely short time, so that orders can be filled very quickly with the measuring coupling of my invention.

Because of the formation of oil passages in the gaps between the teeth 34, there is the problem of supplying the oil to the compression chambers as well as discharging oil therefrom, and this is brought about very effectively with my invention by providing the axially displaced sets of radial bores 31b and 310. The bores 31b communicate with -a larger number of gaps between the teeth 34 than the number of bores 31b, and by way of the annular recess 350 all of the gaps between the teeth 34 are in simultaneous communication with all of the bores 31b which are of a smaller number, so that a very eflicient supply is achieved in this way. In the same way it will be noted that all of the discharge bores 31c communicate with a common annular groove 31 so that in this way also an efficient discharge is guaranteed even for a relatively large number of bores 310.

It is particularly to be noted that with the passage means of the invention the one set of radial bores 31b through the control bores 31:2 and the recesses 32d precisely controls only the supply of oil, while the other control bores 31g coperate with the other recesses 32c to precisely control only the discharge of oil from the compression chambers. Because of this separation of the functions for controlling the supply and for controlling the discharge one from the other, it is of course important to prevent communication between the set of supply bores 31b and the set of discharge bores 310. While it is true that the meshing of the teeth 34a at the inner periphery of the vane disc 31 with the teeth 34 of the hub 33 will, very greatly throttle any flow of oil along the inner periphery of the vane disc between the sets of bores 31b and 310, nevertheless leakage along the inner periphery between these sets of bores cannot be avoided solely by relying on the meshing of the gear teeth, and it is for this reason that the sealing means which includes the ring 42 is provided. Thus, by way of the sealing means 42 any possible communication between the bores 3112, on the one hand, and the bores 310, on the other hand, along the inner periphery of the vane disc 31 is reliably prevented.

It is of course important to avoid any influence of the speed of rotation on the measurements, and for this reason the flow of oil to and from the vane disc 31 takes place at equal radial distances from the axis thereof. This is brought about by the particular diameter of the teeth at the inner periphery of the vane disc and the outer periphery of the sleeve 33 as well as of the races 35 which surround the teeth of the sleeve 33. Of course, it be logical to have the transmitter means 38 also provided with the same inner diameter, which is to say the transmitting means 38 should be slidably mounted on the tips of the teeth 34 of the sleeve 33. As a practical matter, however, such a construction is highly undesirable, and it is to eliminate this drawback that it is proposed with my invention to press the ball bearings and the vane disc as well as all components which surround the hub means directly against each other to form therefrom the equivalent of an elongated fluid-tight pipe which directly surrounds the hub means 33.

Of course, the bearing sleeve 36 forms one of these components in the train of elements which are axially pressed against each other by the ring 37 and the collar 33a. Thus, by the use of this bearing sleeve 36 it is possible to axially press all of the components which surround the hub means against each other While still providing for the pressure transmitting means 38 the mounting derived 'by way of the slide rings 39.

By situ ating the control bores 31c and 31;: for the supply and discharge of the oil at the outer ends of the radial bores 31b and 31c, respectively, these controls take place outwardly beyond the innermost parts of the compression chambers situated at the inner ends of the vanes 32a, so that as a result it is possible to achieve the desired controls with a relatively small degree of angular turning between the vane disc and the rotor housing. Thus, because the controls are displaced to a greater radial distance from the axis of the coupling a smaller degree of angular turning will provide the same controls as a larger degree of angular turning at a location closer to the axis. Therefore, with my invention it is possible to achieve the required controls with a smaller extent of rotary movement and at the same time it is possible to provide also as a result of this feature a relatively large number of vanes with a correspondingly smaller angular spacing therebetween, so that the circumferential distance from one vane to the next is relatively small. Moreover, the manufacturing costs are reduced in accordance with my invention by using for the recesses 32d and 32e simple circular recesses which can be very inexpensively drilled. The milled control recesses heretofore required to take an :arcuate or slot-shaped configuration are completely unnecessary with the structure of my invention, so that in this way without sacrificing any advantages it is possible to reduce the cost.

Thus, it will be seen that with the structure of my invention the improved hydrostatic measuring coupling indeed has an extremely thin-walled hub and an outstanding path of flow for the oil meeting all of the requirements with a large number of vanes and compression chambers. At the same time, the structure of my invention is extremely compact and of small exterior dimensions, providing the best possible solution in this latter respect. This also applies to the universal utility of the structure, since the interchangeable hub means can without any appreciable cost be adapted to any required purpose. Thus, the measuring couplings can be individually manufactured by mass production methods and only when actually supplied to the ultimate consumer need they be assembled with a particular hub means. As a result of this latter feature and also as a result of the simple structure of my invention it is possible to reduce the manufacturing cost of the hydrostatic measuring coupling to such an extent that even from the standpoint of cost nothing stands in the way of the desired practically universal utility of the structure.

I claim:

1. Torque measuring device for coupling a drive shaft to a driven member comprising a vane disc having fluid passage means formed therein and a splined bore extending axially therethrough, hub means extending through said splined bore and adapted to be driven by the drive shaft, said hub means being in the form of a sleeve having axially extending exterior splines for releasably coupling said hub means to said vane disc and for directing fluid to said passage means, means for driving the driven member, said driven member driving means and said vane disc defining compression chambers communicating with said passage means, and pressuretransmitting means communicating with said compression chambers through said axially extending splines for supplying fluid thereto, whereby fluid pressure within said compression chambers and said pressure-transmitting means is indicative of the torque being transmitted from the drive shaft to the driven member.

2. The combination of claim 1 and wherein said hub means has an exterior circumferential surface formed with said passage means for directing said fluid to and from said vane disc.

3. A torque measuring device for coupling a drive shaft to a driven member comprising a vane disc having fluid passage means formed therein and a splined bore extending axially therethrough, a hub member extending through said splined bore and adapted to be driven by the drive shaft, said hub member having axially extending exterior splines for releasably coupling said hub member to said vane diSc and for directing fluid to said passage means, an outer rotor housing surrounding said vane disc and adapted to drive the driven member, said rotor housing and said vane disc defining compression chambers which communicate with said passage means, bearing means surrounding said hub means and supporting said rotor housing for rotary movement, said bearing means including a pair of inner races directly surrounding said axially extending splines and between which said vane disc is located, pressing means carried by said hub means and axially pressing said races and vane disc against each other to form therefrom a fluid tight tubular structure surrounding said axially extending splines, and pressure-transmitting means surrounding said hub member on one side of said rotor housing for supplying fluid to said compression chambers through said axially extending splines, whereby the fiuid pressure within said compression chambers and said pressure-transmitting means is indicative of the torque being transmitted from the drive shaft to the driven member.

4. The combination of claim 3 and wherein said pressure-transmiiting means is carried by said hu: means on said one sid: of said rotor housing. said vane disc being formed, as part of said pass means, in its vanes with oo oo,

12 one set of radial bores through which oil is supplied to said compression cha Myers and axially displaced from said one set of radial bores at the ride of the latter directed away from said. pressure transmitting means with a second set of radial bores through which oil is discharged from said compression chambers, and said passage means including annular passages communicating with all of the gaps between the spines of said hub member as well as with said Sets of radial bores.

5. The combination of claim 4 and wherein said passage means includes one set of axial bores formed in the vanes of said vane disc, respectively communicating with one set of radial bores, and extending respectively therefrom to that face of said vane disc which is directed toward said pressure transmitting means, and said passage means including a second set of axial bores respectively communicating with said second set of radial bores and extending respectively therefrom through that face of said vane disc which is directed away from said pressure transmitting means.

6. The combin tion of claim 5 and wherein said rotor housing has a pair of side walls between which said vane disc is situated and that one of said side walls of said rotor housing which is nearest to said pressure transmitting means being formed with recesses respectively communicating with said one set of axial bores and controlling only the flow of oil to said compression chambers, and the other of said side walls of said rotor housing which is more distant from said pressure transmitting means being formed with a second set of recesses respectively communicating with said second set of axial bores and controlling only the fiow of oil from said compression chambers.

7. The combination of claim 6 and wherein said splined hub member is formed in a plane normal to its axis and situated between said one set of radial bores and said second set of radial bores with an annular groove, and a sealing ring situated in the latter annular groove to prevent communication bctween said one set and said second set of radial bores at that part of said splined hub member which is surrounded by said vane disc.

8. The combination of claim '7 and wherein said splined hub member has extending beyond the splines thereof a smOOthsurfaced cylindrical portion surrounded by said pressure-transmit'ing means, and a bearing sleeve seated on said smooth surfaced cylindrical portion of said hub member and supporting said pressure-transmitting means, said bearing sleeve having inner splines of substantially the same size and angular distribution as the splines of said splined hub member with said inner splines of said bearing sleeve respectively forming extensions of the splines of said splined hub member, and said bearing sleeve being formed at its exterior with an annular groove intersecting its inner splines so as to communicate with the gaps thercbetween and thus through the latter gaps with the gaps between the splines of said splined hub member.

The combination of claim 8 and wherein said rcccsses in said side walls of said rotor housing are respectively in the form of axially bored depressions of circular cross section.

it A torque measuring device for coupling a drive shaft to a driven member comprising a vane disc having fluid passage means formed therein and a splined bore extending axially theretnrough, a hub member extending through said splined bore and adapted to be driven by the drive sha i, said hub member having axially extending exterior splines for releasably coupling said hub member to said vane disc and for directing liuid to said passage means, a rotor housing surrounding said vane disc and adapted to drive the driven member, said rotor housing a..d said vane disc defining compression chambers which 0 nmunicate with said passage means, said pressuretransmitting means surrounding said hub means on one side of said rotor housin said s lined hub means hav- 13 ing an exterior portion provided with a smooth cylindrical surface situated beyond the axially extending splines thereof, and a bearing sleeve surrounding said portion of said hub means which has said smooth cylindrical surface and seated on the latter surface, said bearing sleeve supporting said pressure-transmitting means and having inner splines which respectively form extensions of the splines of said splined hub means, said bearing sleeve being formed with an outer annular groove communicating with the spaces between said inner splines thereof so that said groove communicates through the spaces between said inner splines with the gaps between the splines of said splined hub means, said pressure-transmitting means communicating with said compression chambers through said axially extending splines, whereby the fluid pressure Within said compression chambers and pressure-transmitting means is indicative of the torque being transmitted from the drive shaft to the driven member.

References Cited UNITED STATES PATENTS 2,935,869 5/1966 Shipley 73-436 3,057,193 10/1962 Wiggermann 73136 RICHARD C. QUEISSER, Primary Examiner.

JAMES J. GILL, CHARLES A. RUEHL, Examiners. 

